SIPSIG: Infrastructure ENUM

Event report

On October 11th 2007 in den Hague, Carrier ENUM was the main topic of a conference organized by the Dutch Internet Society SIP Special Interest Group (SIP SIG).

The speakers were: Richard Shockey, Eli Katz, Douglas J. Ranalli, Steve Heap, Arbinet. In the panel discussion led by Adrian Georgescu these four speakers were joined by Willem Verbrugh (COIN) and Ben van Leliveld (VDVL).

Download presentation Richard Shockey: [ PDF ]

Download presentation Douglas J. Ranalli: [ ODF | PDF | Powerpoint 2003 ]

Download presentation Steve Heap: [ ODF | PDF | Powerpoint 2003 ]

Download presentation Eli Katz: [ ODF | PDF |

Summary of the discussion

Adrian Georgescu

ENUM has been originally designed to be a number portability solution and a tool for end users to register and make available their existing E164 number over the Internet. This is known as User ENUM and is currently looking for valid business models while the infrastructure is being setup as we speak in several countries.

The conference was focussed on Carrier ENUM, a way to use ENUM technology by carriers to interconnect Voice over IP calls over the Internet without traversing the PSTN.

Netherlands is a country where the use of both types of ENUM is gaining momentum.

The panel discussion shed light among questions related to how ENUM technology affects the way is business is done in the voice carrier business. Some of the lessons learned from the panel discussion:

• User ENUM was originally intended to enable end-to-end communication between end-points, whereas Carrier ENUM is intended to facilitate the routing of calls between SIP Proxies
• ENUM is not a stand-alone product, it is rather a tool used by SIP Proxies to help them in the routing decision of SIP based calls
• Carrier ENUM provides a tool for man in the middle business models that preserve the way PSTN business used to operate
• ENUM is the only available technology for numbering resources on IP based on DNS
• ENUM is the only recognized method to do an All Call Query number portability method on the Internet
• Technologists are ahead of their time, maybe User ENUM is the right way to do it but not yet
• Number provisioning is the most important technical aspect of Carrier ENUM
• There are two models of charging the use of ENUM, one is per dip or query and the second is per hosting of numbers, the later seem to have more success in adoption
• Carriers should concern the regulator about the way the country level number portability database will interact with the ENUM systems setup
• The carriers will use one way or another ENUM, technically it is not scalable to setup parallel ENUM tries, ENUM based federations solve this problem
• ENUM federations can help solve trust issue, decrease spam, save on bilateral agreement costs
• ENUM federations can settle address resolution, call signaling or/and media based on carrier preferences
• There are meta-solutions on top of ENUM that make possible interoperability between number resolution on both SS7 and IP networks

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